Today started with a good speed work run using a metronome to maintain a cadence of 90 (180 beats per minute). I ran my intervals of 3x500m at a 9:00/mm pace (with 1-minute recovery runs at 10:30/mm pace). I added 5-minute easy runs at 10:00/mm pace between sets.
Maintaining a cadence of 90 made things feel 'different' because I had to work on a new breathing rhythm. That is still a work in progress. But I could see how the lack of a steady breathing rhythm really affected my heart rate. But, I did the whole run in about 42 minutes which was excellent. It was a nice way to wake up, and start the day with 4 miles in the books.
Tonight I had another Natural Running class and it was awesome! We spent a good amount of time talking about Stride Frequency (cadence) and Stride Length to manage speed and running efficiency.
After we did some warming up, we went out for a short run as a group, with the coach running along to watch, make suggestions, and direct the flow. The objective was for us to get used to running at a cadence of 90.
So what is Cadence? Cadence is the number of steps you take in one minute. I usually calculate this by counting the number of steps of my right foot in 30 seconds and multiply that by two. So taking 90 steps in 30 seconds means your steps per minute is 180 (which is where you want to be). At least that is what my trainer tells me.
Some interesting things about cadence. You increase 'speed' by varying your stride length, not your stride frequency (cadence). My trainer told me that the faster your cadence, the less 'air time' you experience. The slower the cadence, the 'higher' you are when airborne, which increases the landing forces on your body, which can cause injury. A faster, consistent cadence can result in a smoother, more efficient running form that lessens impact forces on the body.
It also can make you faster. My trainer got on a treadmill and proved to us that she could maintain a cadence of 90 while increasing/decreasing her speed by adjusting her stride length. Even as her stride lengthened and she sped up, her cadence stayed at 90. This is what the elite runners do. The energy to increase your stride length is much less than the energy it takes to increase your cadence -- hence more efficient running.
In my Natural Running class tonight, we worked on cadence while doing acceleration drills. We sped up and slowed down, but kept our cadence at 90 (using a metronome to help keep us at the right stride frequency). It was awesome! My fastest running pace tonight was 6:30/mm!!! Granted I was only at that pace for maybe 30 seconds but still, that was fast!!
You can read more about it at this site, which talks about cadence and how the elite runners use it for speed and to reduce injury due to excessive stride lengths and impact forces. I am still working on getting comfortable with this whole thing since my usual cadence is between 84-86. But I can see/feel the benefits of getting to 90.